O wild West Wind, thou breath of Autumn's being,Thou, from whose unseen presence the leaves deadAre driven, like ghosts from an enchanter fleeing,Yellow, and black, and pale, and hectic red,Pestilence-stricken multitudes: O thou,Who chariotest to their dark wintry bedThe winged seeds, where they lie cold and low,Each like a corpse within its grave, untilThine azure sister of the Spring shall blowHer clarion o'er the dreaming earth, and fill(Driving sweet buds like flocks to feed in air)With living hues and odours plain and hill:Wild Spirit, which art moving everywhere;Destroyer and preserver; hear, oh, hear!
The last line of the first section, or stanza, tells the two main things Shelley is suggesting that the west wind can do. He calls the strong wind "destroyer and preserver." It is a destroyer because it strips the deciduous trees of all their leaves. It does not kill the leaves; they die naturally with the coming of winter. But it is largely responsible for stripping the trees of all those dead and dying leaves. Otherwise they might cling to the branches throughout the fall and winter. Secondly, the poet calls the wind "preserver." This is because the wind also strips the "winged seeds" from the branches and scatters them across the land along with the dead leaves. The leaves cover the seeds and protect them from the elements during the winter, and then the decaying leaves serve as excellent compost for the seeds when they sprout in the spring.

The first thing the wind is given credit for is located here in the opening lines of the poem. The wind is given credit for driving the fallen leaves from their place. Shelley uses the wind as a "breath of Autmn" giving the reader a visual of dead leaves on the ground being blown about by the wind, the classic fall time scene.

Yellow, and black, and pale, and hectic red,

Pestilence-stricken multitudes: O thou,

Who chariotest to their dark wintry bed

The wind is now being credited with taking the dying leaves but also carrying them to their "wintry bed". The poem ostensibly about the wind blowing about the dead leaves of winter can be seen to be about death, where the west wind is actually fate coming to take the dying people to their graves. This view of the poem is born out in the first stanza when Shelley begins to call out to the "Wild Spirit" as the "destroyer and preserver".